Hey I'm pretty new to batteries and haven't have any experience with them. I just upgraded from a iStick to a sigelei 50w and have 2 of the samsung 18650 batteries. I'm looking for a charger for the batteries cause I don't want to keep using a usb to charge and since I have two, I don't want to wait for one to finish charging and then charge the other one. I'm wondering if the nitecore d2 charger will be good as a charger? Or what is the best charger for the two batteries?